• 한국안전학회지
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• 제19권2호
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• pp.104-111
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• 2004

The aim of this study was to investigate the influence of inorganic pigments on the physical properties of cement mortar. For this purpose, the compressive strength and absorption test were carried out on cement mortar imxed with inorganic pigments by changing the proportion of cement mortar, water-cement ratio, and ratio of pigment. The result of this study can be summarized as follows: the compressive strength of colored mortar rapidely increased in red and yellow mortar, as the mix ratio of pigment increased. In case of green and black mortar, however, the compressive strength decresed as the mix ratio incresed. In case of red and yellow mortar, the absorption of colored mortar increased as the mixing ratio increased, if the mean particle diameter of the pigment is small. In case of green and black mortar, the absorption ratio decreased as the mix ratio increased. After investigating the overall physical properties of colored mortar, it was confirmed that the proper mix ratio of pigment securing the properties of colored mortar was below 6% of the weight of the cement to be used.

• 한국의류학회지
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• 제41권6호
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• pp.1109-1123
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• 2017

This study analyzed a somatotype of teenager's that was suitable to improve the reality of a virtual model size. We analyzed 843 teenagers 12-18 years old from the 6th Size Korea data. First, factor analysis was done for abstracting new criteria and dividing the somatotype; subsequently, we selected the waist height proportion to stature (body proportion) and drop (torso shape). Next, the cluster analysis was done with these criteria; subsequently, 5 body proportion types and 7 torso shapes were distinguished. A virtual model size for 4 somatotype with more than 50 persons was also designed by a regression analysis that constituted sizes for each factor. The designed model size was compared with body size as well as with Clo's virtual model size. The research model showed a high similarity in sizes with body as well as improved reality over the Clo model that presented size problems such as low waist height, bigger bust, and smaller thigh circumference than the real body.

• Smart Structures and Systems
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• 제10권6호
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• pp.573-591
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• 2012

In this study, a procedure to design an optimal LCVA that maximizes the equivalent damping ratio added to the primary structure subjected to along-wind excitation is proposed. That design procedure does not only consider the natural frequency and damping ratio of the LCVA, but also the proportion of the U-shaped liquid, which is closely related to the participation ratio of the liquid mass in inertial force. In addition, constraints to ensure the U-shape of the liquid are considered in the design process, so that suboptimal solutions that violate the optimal tuning law partly are adopted as a candidate of the optimal LCVA. The proposed design procedure of the LCVA is applied to the control of the 76-story benchmark building, and the optimal proportions of the liquid shape under various design conditions are compared.

• Korea-Australia Rheology Journal
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• 제19권1호
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• pp.35-42
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• 2007

The effects of particle size distribution on the magnetorheological response of inverse ferrofluids was investigated using controlled mixtures of two monodisperse non-magnetisable powders of sizes $4.6\;{\mu}m\;and\;80{\mu}m$ at constant volume fraction of 30%, subjected to large amplitude oscillatory shear flow. In the linear viscoelastic regime (pre-yield region), it was found that the storage and loss moduli were dependent on the particle size as well as the proportion of small particles, with the highest storage modulus occurring for the monodisperse small particles. In the nonlinear regime (post yield region), Fourier analysis was used to compare the behaviour of the $1^{st}\;and\;3^{rd}$ harmonics ($I_{1}\;and\;I_{3}\;respectively$) as well as the fundamental phase angle as functions of the applied strain amplitude. The ratio of $I_{3}/I_{1}$ was found to become more pronounced with decreasing particle size as well as with increasing proportion of small particles in the bidisperse mixtures. Furthermore, the phase angle was able to clearly show the transition from solid-like to viscous behaviour. The results suggested that the nonlinear response of a bidisperse IFF is dependent on particle size as well as the proportion of small particles in the system.

• 한국세라믹학회지
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• 제16권3호
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• pp.178-183
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• 1979

The carborundum abrasive specimens bonded with a soda-borosilicate glass were prepared. Samples fired at specified temperatures with various mixing ratio and forming pressure were examined in terms of the structure, bonding strength, and microscopic observations. Increasing the forming pressure up to 400kg/$\cm^2$, the structure became denser in proportion to the forming pressure. The bonding strength was generally increased with increasing the mixing ratio (Vb/Vg), but the bloating phenomena were observed when samples were fired above 95$0^{\circ}C$ with mixing ratio above 20%, consequently, the bonding strength was decreased. Samples fired at the temperature range 900~95$0^{\circ}C$ with mixing ratio 15~30% had the dense structure with various grades.

• 한국작물학회지
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• 제55권1호
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• pp.83-90
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• 2010

수년 동안 국내 전역에서 수집된 수수 179 유전자원을 공시하여 작물학적 특성조사를 통한 품종육성의 기초자료를 제공코자 수행하였던 바 그 결과를 요약하면 다음과 같다. 1. 수수의 수형은 산수형, 소경수수형, 반소경수수형, 극밀수형, 및 밀수형의 5가지 수형이 존재하였으며, 수형별 빈도를 보면 소경수수형이 38.0%(68자원)로 가장 많았으며, 극밀수형 및 밀수형이 각각 16.2%, 7.8%로 가장 적었다. 2. 수수 이삭의 까락 유무는 28.5%(51자원)가 까락을 갖고 있었으며, 나머지 71.5%(128자원)는 까락이 없는 것으로 분류되었다. 3. 종실형태는 43.0%(77자원)가 원형으로 가장 많이 차지하였으며, 편원형이 7.3%(13자원)로 가장 적었다. 종피색은 황갈색이 84.4%(151자원)로 가장 많았으며, 갈색 및 흰색이 똑같이 1.1%로 가장 적었다. 4. 수수 179자원의 출수소요일은 67~88일의 범위를 나타내어 변이폭이 컷으며, 평균은 77.4일이었다. 출수소요일의 분포는 179자원 중 76~80일이 37.4%(67자원)로 가장 많았으며, 86일 이상도 5.6%이었으며, 70일 이전에 출수한 자원도 10.0%를 나타내었다. 5. 간장은 92~360 cm의 범위를 보였으며, 평균은 253.8 cm로 변이의 폭이 컷다. 간장의 분포는 291~310 cm가 20.6% (37자원)로 가장 많았다. 6. 수장은 15~49 cm의 범위를 보였고, 평균 28.8 cm이었다. 수장의 분포는 31~35 cm가 26.3%(47자원)로 가장 많았으며, 15 cm 이하가 0.6%로 가장 적었다. 7. 생육일수는 110~146일의 범위를 나타내어 변이 폭이 상당히 큼을 알 수 있었고, 평균은 125.5일이었다. 생육기간의 빈도는 111~115일이 39.7%(71자원)로 가장 많았으며, 110일 이하와 141일 이상에 속하는 자원도 각각 2, 23자원이나 되었다. 8. 1수립수의 범위는 163~4,532개로 변이 폭이 상당히 컷으며, 평균은 2,068.6개 이었다. 1수립수 분포는 1,601~2,000개가 25.7%(46자원)로 가장 많았다. 9. 공시된 179 유전자원의 1000립중은 범위가 10.6~38.1 g으로 변이폭이 컷으며, 평균은 25.6 g이었다. 1000립중의 분포는 26.0~30.0 g가 전체의 44.1%(79자원)로 가장 많았다

• KCI Concrete Journal
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• 제11권3호
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• pp.19-28
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• 1999

This study treated self-compacting high Performance concrete as two Phase materials of Paste and aggregates and examined the effect of powder and aggregates on self-compacting high performance, since fluidity and segregation resistance of fresh concrete are changed mainly by paste. To improve the fluidity and self-compactibility of concrete, optimum powder ratio of self-compacting high performance concrete using fly ash and blast-furnace slag as powders were calculated. This study was also designed to provide basic materials for suitable design of mix proportion by evaluating fluidity and compactibility by various volume ratios of fine aggregates, paste, and aggregates. As a result, the more fly ash was replaced, the more confined water ratio was reduced because of higher fluidity. The smallest confined water ratio was determined when 15% blast-furnace slag was replaced. The lowest confined water ratio was acquired when 20% fly ash and 15% blast-furnace slag were replaced together. The optimum fine aggregates ratio with the best compactibility was the fine aggregate ratio with the lowest percentage of void in mixing coarse aggregate and fine aggregate In mixing the high performance concrete. Self-compacting high performance concrete with desirable compactibility required more than minimum of unit volume weight. If the unit volume weight used was less than the minimum, concrete had seriously reduced compactibility.

• 분석과학
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• 제18권4호
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• pp.292-297
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• 2005

붕산수를 중성자 조사하였을 때 발생하는 화학특성 변화를 측정하였다. 붕산 용액의 pH는 조사시간과 붕산농도가 증가할수록 감소하였다. 물의 방사분해물인 과산화수소는 붕산농도에 비례하였고 조사시간에는 반비례하였다. 기체 방사분해물인 수소와 산소기체는 당량비로 생성되었다. $^{10}B(n{\cdot}{\alpha})^7Li$ 핵반응으로 생성된 Li과 조사시간과의 상관관계는 낮은 붕산 농도범위에서는 좋지 않았으나 높은 농도범위에서는 비례성이 다소 좋아지는 현상을 발견하였다.

• 한국분무공학회지
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• 제14권3호
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• pp.122-130
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• 2009

Vegetable oil and its derivatives as an alternative diesel fuel have become more attractive recently because of its environmental benefits and the fact that they are made from renewable resources. Viscosity is the most significant property to affect the utilization of vegetable oil and its derivatives in the compression ignition engines. This paper presents the existing correlations for predicting the viscosity of vegetable oil and its derivatives for compression ignition engines. According to the parameter considered in the correlations, the empirical correlations can be divided into six groups: correlations as a function of temperature, of proportion, of composition, of temperature and composition, of temperature and proportion, and of fuel properties. Out of physical properties of fuel, there exist in the literature several parameters for giving the influence on kinematic viscosity such as density, specific gravity, the ratio of iodine value over the saponification value, higher heating value, flash point and pressure. The study for the verification of applicability of existing correlations to non-edible vegetable oil and its derivatives is required.

• 한국세라믹학회지
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• 제46권6호
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• pp.657-661
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• 2009

In this study, rheological properties of cement pastes containing ground Finex-slag (4000, 6000, 7000 c$m^2$/g) were investigated bymini-flow test and coaxial cylinder viscometer. And also blast furnace slag(4000, 6000, 7000 c$m^2$/g) were used for comparison. According to the experimental results, Finex-slag and blast furnace slag showed very similar trend in the rheological properties of the cement pastes. The fluidity of cement pastes blended Finex-slag and blast furnace slag powder were improved by high replacement ratio. In the relationship of plastic viscosity and yield stress appeared the tendency of the proportion greatly. And in the relationship of plastic viscosity, yield stress and mini-flow appeared the tendency of the inverse proportion.